1. Technical Field of the Invention
This application is based on applications Nos. 9-099853 and 9-128620 filed in Japan, the contents of which is hereby incorporated by reference.
The present invention relates to an image recording device, and particularly to an image recording device of such type as to record images by ejecting ink or toner from a print head onto a sheet or by directing a light beam in accordance with image data while the sheet is transferred in a direction crossing at right angles with the recording direction, and further to a sheet feeding mechanism incorporated in such an image recording device.
2. Description of Related Art
A conventional sheet feeder incorporated in an image recording device as mentioned above is usually provided with a separating pawl disposed and contacted at both sides of a leading edge of the sheets for effecting reliable separation of recording sheets sent out by feeding rollers.
It is also a known art to provide a pawl position changeover mechanism with which the separating pawl is retreated to a non-effecting position for preventing the pawl from being an obstruction to the feeding of thick or hard sheets. An operative lever of such pawl position changeover mechanism is normally disposed on the side of a sheet feeder tray.
Also, in order to record high-quality images, it is necessary to maintain a prescribed distance between a print head and the recording sheet. It is thus required to change over the distance between the print head and a platen in accordance with the thickness of the recording sheets, and it has been proposed to provide a head position changeover mechanism for switching over the position of the print head. An operative lever of this head position changeover mechanism is normally provided on a carriage on which the print head is mounted, or disposed on a supporting member of a guide shaft of the carriage.
For conveying various types of recording sheets, it is necessary to change the positions of the separating pawl and the print head depending on the thickness or resiliency of the sheets. Operation of two different operative levers is thus required for the changeover. Moreover, the operative lever of the head position changeover mechanism is disposed within the cover of the main device body, making the switchover operation highly troublesome. When the changeover operation is forgotten, the sheets are supplied in an inappropriate setting condition, thus inducing feeding errors or recording errors wherein the recording sheets are stained by contacting the print head.
Also, for an image recording device described above, it is recommended to use special type of paper for achieving image forming of highly fine quality. Such special paper is generally covered with a coating in which a multiplicity of minute pores are formed, through which the ink deposited on the surface of the paper is led under the coating.
However, when a roller or the like is tightly pressed on the coating, the pores in a portion that is pressed are destroyed thus being disabled to lead the ink under the coating. Also, the ink deposited in the portion that is pressed by the roller may splatter, causing printing errors. As a result, the quality of printed images sometimes varies between the parts pressed by the roller and those that are not.
Also, when the roller contacts with a portion where the ink has been deposited on the sheet which has been passed through a printing section, the ink that is not fully dried may attach to the roller, which may be offset to a next sheet. Therefore, in the discharging section of a printer or the like, a star wheel is provided instead of the roller for conveying sheets. However, star wheels have a very small contacting area with the sheets thus being incapable of supplying a sufficient amount of conveying force to the sheets. The sheet feeding mechanism incorporated in conventional image recording devices have such problems as described above that images may be damaged or the sheets cannot be conveyed with a sufficient amount of force.